Tough on Chemicals, Gentle on Gear

Courtesy Photo | Random heteropolymer (RHP) primary sequence and predicted structure in solvent. The chemical pieces that compose the RHP are shown as colored dots in a string. Below them, computational modeling predicts RHP structure in different solvents. (UC Berkeley image)  

FT. BELVOIR, VIRGINIA, UNITED STATES

11.07.2023

Courtesy Story

Defense Threat Reduction Agency's Chemical and Biological Technologies Department

Newly developed synthetic polymer enzymes may provide an effective alternative to harsh chemical warfare agent (CWA) decontaminants for Joint Force equipment, such as motor vehicles and unmanned sensors. After military equipment is contaminated with CWAs, warfighters must rapidly and thoroughly decontaminate it to reduce Mission Oriented Protective Posture, maintain combat power, and continue their mission. Current decontamination processes use strongly reactive chemicals, such as caustics or bleach, to neutralize and destroy CWAs on equipment surfaces. While this process effectively destroys CWAs, the harsh decontaminants can damage or corrode equipment material and impact mission performance. Because of this adverse consequence, the Joint Force seeks decontaminants that have no negative impact on equipment materials but possess the capability to effectively neutralize a broad range of CWAs.

Natural protein enzymes are one class of decontaminant that is gentle on materials but also able to effectively destroy CWAs. Naturally occurring protein enzymes, called organophosphates, degrade nerve agents through catalysis, where one protein molecule can neutralize many agent molecules. However, to function efficiently as decontaminants, natural organophosphates must work in environments with narrow temperature ranges (near 98.6 degrees F) and need enough water to keep the surface wet during decontamination. Natural organophosphates are poor candidates for field decontamination because nerve agents don’t dissolve well in water and operational environments vary widely in temperature.

The Defense Threat Reduction Agency’s (DTRA) Chemical and Biological Technologies Department in its role as the Joint Science and Technology Office (JSTO) for Chemical and Biological Defense, an integral component of the Chemical and Biological Defense Program (CBDP), invested with the University of California, Berkeley to develop novel, robust synthetic decontaminants that mimic natural biological protein enzyme structure and function.

Recently, UC Berkeley developed a platform for designing biomimetic synthetic polymer enzymes that work with similar effectiveness as natural protein enzymes but function in a broader environmental and solvent range. To do this, the UC Berkeley team surveyed nearly 60,000 proteins to derive and understand the common rules for protein design. Using this database, they created a map of protein sequences with links to specific chemical characteristics. They then synthesized a small group of molecules similar to natural amino acids and used them to create a library of random polymers designed to mimic protein mixtures in biology. The result was a new class of molecules called random heteropolymers (RHPs) with protein-like characteristics but without some protein enzyme environmental limitations.

The UC Berkeley team tested the RHPs for protein characteristics, such as the ability to interact and bind with other natural proteins and carry out enzymatic reactions. They demonstrated that stable RHPs could catalytically destroy CWA simulants in a wide range of temperatures and in solutions containing organic solvents, such as oils and alcohols, and detergents, as well as in water solutions. This is important because CWAs dissolve readily in detergents and organic solvents, which improves both neutralization and removal from surfaces.

The benefit of this research extends beyond decontamination applications. Using the existing data set of thousands of protein structures proved an efficient way to gather information, identify and extract critical biomimetic design features, and isolate those features from a randomly generated library of synthetic heteropolymers. Demonstrating that this information-driven design platform enables engineering of biomimetic molecules that can catalyze CWA destruction strongly suggests that new molecules can be designed and created with any desired enzymatic activity.

In the future, decontaminants based on RHPs will benefit the Joint Force by providing an alternative technology that won’t damage materials, works in both aqueous and organic solutions, and will rapidly and catalytically neutralize CWAs without hazardous waste, and rapidly destroy CWAs at all temperatures, even below freezing. This will reduce the time, cost, and risk associated with returning equipment back to service.

POC: Tracee Whitfield, Ph.D., [e-mail]

• Date Taken: 11.07.2023
• Date Posted: 11.07.2023 21:29
• Story ID: 457433
• Location: FT. BELVOIR, VIRGINIA, US